You didn't mention your viewing distance. They're both decent enough looking sets. The Vizio is indeed LED-backlit, apparently with some rudimentary type of local dimming (which, according to CNet, doesn't work), but it's smaller. I am pretty sure they're both actually 60hz TVs with some type of backlight scanning. LG is known for doing this, and the Vizio lists a "120Hz effective refresh rate. The Vizio should offer better backlight uniformity, but I have seen both and can't really discern a major difference between the two. I would go for the LG -- the TV will tend to shrink a bit after you get it, so it's always good to buy as big as you can afford. Take the $70 you save and put it towards a Blu-Ray player/streaming box or something for decent sound (they both sound pretty abysmal).
desktop + headphone Sonus faber Toy monitor|REL T Zero|Sony UDA-1|Sony MDR-Z7|Sony MDR-1000X|Audioquest NightHawk|Ultimate Ears Triple.fi 10|Sony NW-A35
ht Sony A1E 65" OLED|Monitor Audio Silver RX6, RX Centre, RX1|SVS SB-2000|Sony STR-ZA5000ES|Sony UBP-X1000ES|Sonos Connect + Peachtree Audio DAC•iT|Panamax M-5100PM
stereo Sonus faber Toy tower|REL S/5|Teac UD-501|Sony TA-A1ES|Sony SCD-777ES|Sony ST-SA50ES|Sony 43" X800D|Sony UBP-X800|Sonos Connect|Furman Elite-15 PFi